#define MAXLEN 1024
 
 
 int main(int argc, char* argv[])
 {
     u_char no = 0;
     u_int yes = 1;      
	int send_s, recv_s;     
	u_char ttl;
	struct sockaddr_in mcast_group;
	struct ip_mreq mreq= {};
	struct utsname name;
	int n;
        socklen_t len;
        struct sockaddr_in from;
        char message [MAXLEN+1];
 
     if (argc != 3) {
         fprintf(stderr, "Usage: %s mcast_group port\n", argv[0]);
         exit(1);
     }
 
     memset(&mcast_group, 0, sizeof(mcast_group));
     mcast_group.sin_family = AF_INET;
     mcast_group.sin_port = htons((unsigned short int)strtol(argv[2], NULL, 0));
    mcast_group.sin_addr.s_addr = inet_addr(argv[1]);
//       mcast_group.sin_addr.s_addr = INADDR_ANY;
     
     if ( (recv_s=socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
         perror ("recv socket");
         exit(1);
     }
 
     if (setsockopt(recv_s, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
         perror("reuseaddr setsockopt");
         exit(1);
     }
 
     if (bind(recv_s, (struct sockaddr*)&mcast_group, sizeof(mcast_group)) < 0) {
         perror ("bind");
         exit(1);
     }

    	/* Preparatios for using Multicast */ 
	//mreq.imr_multiaddr = mcast_group.sin_addr;
	mreq.imr_multiaddr.s_addr = inet_addr("239.192.100.1");
//        mreq.imr_interface.s_addr = INADDR_ANY;
      	mreq.imr_interface.s_addr = inet_addr("192.168.4.228");

	if (setsockopt(recv_s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
	perror ("add_membership setsockopt");
	exit(1);
	}
 
	len=sizeof(from);
                if ( (n=recvfrom(recv_s, message, MAXLEN, 0, 
                                 (struct sockaddr*)&from, &len)) < 0) {
                     perror ("recv");
                     exit(1);
                 }
                 message[n] = '\0'; 
                 printf("%s: Received message from %s, size=%d !!\n", 
                         name.nodename,
                         inet_ntoa(from.sin_addr), n);
                 printf("\t%s \n", message);


}